Images

Classifications

F41G7/20—Direction control systems for self-propelled missiles based on continuous observation of target position

F41G7/24—Beam riding guidance systems

G—PHYSICS

G01—MEASURING; TESTING

G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith

G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves

1 This invention relates, generally, to the use of ultra-high frequency radio waves for controlling bombs and other explosive missiles such as rocket missiles, aerial torpedoes, shells, etc., after the same have been discharged from their releasing or projecting apparatus and during flight. This application is a continuation-inpart of Patent No. 2,414,103, granted January 14, 1947, for Apparatus for Controlling a Missile in Flight.

Owing to the constantly increasing height at which military aircraft navigate, it is highly desirable to control explosive projectiles or missiles such as bombs, aerial torpedoes, shells, rockets, etc., after they have left the airplane or the ground as the case may be, in order to correct for the initial sighting errors and other errors including drift errors due to variation of side winds at varying altitudes. Thus, in firing at an aerial target from a ground installation, initial errors present at the time of the projection of the missile are generally augmented by the varia tions of the missile trajectory due to such things as wobbling of the missile, variation in the wind direction and speed with changing altitude or change in the speed or direction of movement of a moving target.

The principal object of the present invention is to provide novel apparatus for controlling bombs, and other explosive missiles such as rocket missiles, aerial torpedoes, shells, etc., after the same'have started their courses and in continuing such control until the target is actually reached by the missiles whereby the latter are caused to hit the target or to explode at substantially their nearest approach thereto.

Another object of the present invention is to provide an ultra-high frequency transmitter adjacent the point at which the shell or other missile is released, the missile being equipped with suitable ultra-high frequency radio receiving apparatus and a servo-mechanism controlled therefrom for effecting transverse movement of the missile in accordance with signals received from the transmitter.

A further object of the present invention is to provide fire control means wherein a gun is directed in accordance with the predicted future position of target as obtained from a fire control predictor, radio means being provided for con- 2 trolling the gun projectile after the same leaves the gun and for directing the same onto the target.

A further object of the invention is to provide means for utilizing the position data of a target as determined by an anti-aircraft fire director for positioning the electromagnetic beam radiating means so that the projectile will traverse a trajectory leading to the predicted future position of the target thereby eliminating the necessity of the projectile chasing the target.

Other objects and advantages will become apparent from the specification, taken in connection with the accompanying drawings wherein the invention is embodied in concrete form.

In the drawings,

Fig. 1 is a schematic view illustrating one use of the apparatus of the present invention.

Fig. 2 is, in part, a sectional view of a proj ectile equipped with a position sensitive receiver and servo-mechanism.

Fig. 3 is a graph illustrating the system of Figs. 1 and 2.

Fig. 4 is a sectional view along line 4-4 of Fi 2.

Similar characters of reference are used in all of the above figures to indicate corresponding parts.

In Fig. 1 there is diagrammatically illustrated a typical embodiment of the present invention wherein an anti-aircraft fire director, generally designated by numeral H, is employed for controlling the orientation of a radiating antenna means I3 and the fire of a universally mounted missile launching device or propellant here shown as a gun I 4. The antenna means i3 is fed from an ultra-high frequency transmitter 15 as of the type disclosed in Patent No. 2,242,275 of R. H. Varian dated May 20, 1941, for delivering to a transmitter antenna I1, ultra-high frequency carrier waves having a frequency of the order of 10 cycles per second, such waves being subject to propagation in substantially straight lines and also having the property of penetrating fog, etc. and not being appreciably interfered with by uncontrollable natural phenomena such as atmospherics or radiation from the sun. The antenna I! is shown provided with a parabolic reflector l9 which has a diameter preferably twenty or more times the wavelength used,

whereby this reflector has high resolving power and produces a highly directional beam of electromagnetic energy. The reflector I9 is shown carrying a telescope 2! that has its line of vision parallel to that of the electromagnetic radiation beam projected from the antenna ll. The telescope 2! is rigidly mounted on reflector 19 for conjoint movement therewith for a purpose to be described below.

It is known that, even with the most highly developed types of fire control directors, the percentage of direct: hits or near misses obtained is relatively low; This'fact is, in a large measure, due to conditions which are beyond the control or influence of the director system, as for ex ample, 'the failure of the target to? maintain constant flight path, or variationin.conditions encountered by the missile in flight. In accordance with the present invention, remote control radio means are provided for inserting a correction in the path of a missile which is observed by means of telescope 2: to be-oiftarget;?"' The. correction is introduced at a time when :the Thissile nears its closest approach to the target, so that an otherwise-complete. miss maybe converted to a direct hit or-a nearv miss Such a correction is inserted under the influence of the highly directional: beam ofmelectromagnetic energy'producedrby the antennameans l3 and transmitter f coasting with the radio-controlled missile illustratedi-in FigrZland particularly described inthe above-mentioned Patent No. 2,414,103.

In theevent of bombardment through the overcast, the telescope 2 i may. be omitted and the observationofLthe missile may bemade by asuitable radio direction and range indicating system ofrthe typedescribed. in-copending application Serial No. 406,494,filed August 12, 1941.

As shownin Fig; l, the anti-aircraft fire direc tor H, which may be of any conventional type, as for example, that disclosed in Patent. No. 2,065,303 forApparatus for the Control ofGunfire, .suppliesitarget position data to the gun Hi throughcable '23 and a conventional servomechanism 25' for control in azimuth and through cable 2'! and a conventional servo mechanism 29 for control in elevation.

The output of the-azimuth servo 251is operatively coupled to the gun H! by means ofa shaft 3| and gear 33 that meshes with therteeth of aring gear 35 rigid with a turntable 3i" on..which the gun it is mounted for azimuthal movement. Similarly, the output of the elevational. servo 29 is operatively coupledto' the gun M by means of shaft 39', gears 4|, 43 and shaft lfi which is adapted to move the gun i l in elevation. In'this way, when the director is correctly operated, the gun It is correctly oriented to project the'missile to interceptthe target at'its future position.

The antenna means 53 is mounted on a turntablefi-l' for simultaneous azimuthal rotation with the gun turntable 3l', said turntable 41 being coupledto the table 37 by gear 35 in mesh with ring gear M which is rigidly connected to the table 41. Gear lie-is driven by, shaft 53 which in turn is coupled through gear 33 and friction slip clutch 55 to shaft 3|. Gears El, 59 together with friction slip clutch BI and shaft 63 operatively connect antenna means l3 to shaft 39 for simultaneous elevational movement with the gun For the purpose of producing relatively fine movement of the antenna means l3 in order to insert the above-mentioned slight correction in the trajectory of the missile, there are provided hand cranks 65, 61, which through gears 66 and 69 and the slippage of the clutches 55, 6|, respectively, make possible azimuthal and elevational movement of the antenna means IS without affecting the position or movement of gun It.

While the operation of the improved fire control system will hereinafter be described in connection with a radio control missile ll shown in Fig. 2, it is to be understood that the present invention is not limited or restricted to this particular type of missile, since other types, as for example, thoseillustrated, described and claimed in copending' applications Serial No. 468,308, filed December '7, 1942, and Serial No. 591,724, filed concurrently herewith, may be used with equally satisfactory results;

While the target is being tracked by an observer operating the fire control director H and the gun I4 is beingpositioned in accordance with information'derlvedfrom the director and transmitted to 'the' guntable through the servo mechanisms- 2-5; 29, the missile l! is launched so as to put it at the predicted future position of the target. A radio control operator energizes the antenna means l3 as the missile nears the target producing ahighlydirective beam of electromagnetic' energy, asgraphica-lly shown in Fig. 3, and

at the'same time observes the target through the telescope 2i. If the observer notices, that; as the missile nears the distance' of closest approach with the target, a complete miss isabout'tobe experienced, the observer may, by 'meansof the hand cranks 65, 61, shift the position of the antenna means to insert a slight correction in the missiles trajectory, steering it enough to put it on or very close to. the target.

The ultra-high frequency radio output of'the transmitter antenna means 3 is adapted to he received by four antennae, three of which are shown at E3, E5 and IT, carriedby the missile H.

Antennae l3, 15 are spaced an appreciable distance apart as byplacing these antennae on the outer edges of opposed fins [9. Similarly, the antennae 'iland a similar one (not shown) are spaced appreciably apart'as by being located on the outer edges of'fins 81 extending. at right angles to the planeof fins 79' carrying antennae 73,15.

In Fig. 2 the antennas 1-3; '75 are shown as dipoles connected through concentric lines 83, 85 t0 any conventional multichannel radio receiver 86, the outputs of which are connected respectively to solenoids 8'3 89 arranged for opposite actuation of armatures 9|, 93 connected 4 to pistons 9550f a balanced valve 91. The-central portion of valve 9 is supplied with compressed air or carbon dioxide gas from atanlr' 99 through pipe IBI. When carbon dioxide is used it may be carried in liquid form in tank Qt. Valve 91 has two upper pipes 503 and H15 that: have their outer portions extending radially within the cylindrical body of the'missile H in opposite directions," the common. axis of theseiportionsiof the pipes H33, H85 passing preferably through the center of gravity ofthe missile. The outer ends of'the' pipes I03, 25 projectrthroughthe housing of the'missile for deliveringcompressed air or carbon dioxide gas in opposite directions diametrically of the missile. Theradial portions of pipes I63, I05 lie in the vertical planealso containing the spaced antennae 1 3,. '55.

,The' antennae ll and the one diametrically opposed thereto are similarly connected to areceiver circuit, such as shown in Fig. 2 for controlling the operation of' solenoids I01, 199, shown in Fig. 4, the armatures of these solenoids being employed for operating th balanced valve Ill similar to valve 91, valve I H controlling the flow of compressed air from the pipe lill to two outwardly extending pipes H3, H5 extending through the wall of the missile H for directing air or carbon dioxide blasts in diametrically opposite directions. The radial portions of pipes H3, H5 lie in the plane of the corresponding antennae.

After projecting the missile and before the same has reached its target the radio observer looks through the telescope 2i and observes the target.

As the missile approaches the target, the latter moves into the field of vision of the observer looking through the telescope 2i although the target is probably not in the central line of sight of the telescope at this time. If the transmitter I5 is producing a pencil beam of ultra-high frequency electromagnetic radiation the field intensity of any cross section of which is greatest at the center of the beam and tapers oil in substantially the fashion shown in Fig. 3 to the side edges thereof, the missile will ordinarily line itself up with the center of the beam. Assuming that the missile is not initially lined up with the center of the beam then due to the varying field intensity of the beam across its cross section one of the antennae 13 or 5, for example, will receive more energy than the other, so that the output of one channel of receiver 86, for example, will be made greater than that of the other channel, whereby solenoid 81 is energized to a greater extent than solenoid 89 so that the balanced valve 91 is moved to uncover pipe I03 thereby causing tank 99 to discharge compressed air or gas through valve 91 and pipe I03 and eifecting a movement of the missile toward the center of the radiating beam, i. e., toward the left in Fig. 3. Similarly, if antenna H, for example, should receive more energy than its diametrically opposed antenna it would act to shift the missile transversely in the plane of these antennae to bring the missile into the central axis 1 ll of the radiating beam corresponding to the center of the line of sight of the telescope 21. Just befor the projectile is about to strike the target, the radio observer gradually shifts the telescope 2| and the antenna means 13 angularly by means of hand cranks 65, 61 so as to bring his line of sight and hence the missile into the direct line of the target so that the latter will be hit as desired.

It will be noted from Fig. 3 that as long as the missile is lined up with the center of line Ill of the radiating electromagnetic beam, the antennae will receive equal intensity of signal so that the balanced valves 91, ill will be held in their neutral positions so that the outputs of the various amplifiers will be equal. Should the missile commence to move out of the center of the beam the antennae will receive signals of unequal strength resulting in the operation of the servo-mechanism and the movement of the missile transversely back into the center of the radiating beam. Owing to the high pressure of the air or gas within the tank 99 and to the fact that the period of time of flight of the missile is short, the flow of air or gas through pipes I03, I05 and H3, H5 is quite rapid so that the reaction force of the jets issuing from these pipes is large, thereby resulting in an immediate response of the missile to any deviation of the same from the path of the beam effecting a rapid return of the missile to the beam.

To further increase the probability of direct hits or near misses, a radio-controlled automatically detonated missile of the type described in copending application Serial Number 468,308, filed December '7, 1942, may be utilized.

There has thus been described an improved fire control system whereby a missile may be launched at a target in accordance with information derived from fire director means and, when it is observed that a complete miss is to be experienced, a correction in the trajectory of the missile may be introduced to direct the missile toward the target.

As many changes could bemade in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Fire control apparatus for controlling the flight of missiles comprising means for projecting a missile, a computer for positioning said projecting means for causing the missile to follow a desired predicted course for obtaining collision with a target, means for sighting the missile and the target as these elements approach each other, and means for projecting a pencil beam of electromagnetic energy toward the missile and target, said beam having a field intensity which is a maximum along its axis and tapers ofi progressively at successive points removed therefrom, said missile having steering means responsive to variations in the field intensity of said beam and means for adjusting said beam projecting means for correcting the direction of said pencil beam and the course of said missile to produce a collision course between said projectile and the target.

2. Fire control apparatus for controlling the flight of missiles comprising means for projecting a missile, a fire control computer for positioning said projecting means for causing the missile to follow a desired predicted course for obtaining collision with a target, means for sighting the missile and the target as these elements approach each other and for determining a correction course for the missile, and means for projecting a pencil beam of electromagnetic energy toward the missile and target, said beam having a field intensity which is a maximum along its axis and tapers oil progressively at successive points removed transversely therefrom, said missile having steering means responsive to variations in the field intensity of said beam and means for adjusting said beam projecting means for correcting the direction of said pencil beam and the course of said missile to produce a collision course between said projectile and the target.

3. Fire control apparatus for controlling the flight of missiles comprising means for projecting a missile, a fire control computer, a servo mechanism connecting said computer to said missile projecting means for positioning the latter to cause the missile to follow a desired predicted course, telescopic means for sighting the missile and a target and for determining a correction course for the missile, a directional electromagnetic radiator for projecting a pencil beam of electromagnetic energy toward the missile and target, said beam having a field in- 7 tensity that isat itsumaximum alon its ax andpers fir pr g essively ransversely he from, radio. rec i er. and, ser mechan sm, n said missile fqrvsteering the same in response to variations in -.t he =fie1dintensity of said beam, and manuallycontrolled means for adjusting said-beam radiating meansfor correcting the direction of said pencil beam and hencethe course of" said missile v to produce a desired collision course between the target and the, missile.